This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | 3 |
| 3 | -16 |
| 4 | 121 |
| 5 | -1181 |
| 6 | 14114 |
| 7 | -199543 |
| 8 | 3257139 |
| 9 | -60279214 |
| 10 | 1247164055 |
| 11 | -28525394481 |
| 12 | 714681439212 |
| 13 | -19465007759913 |
| 14 | 572609747089735 |
| 15 | -18093710202583480 |
| 16 | 611202186074834221 |
| 17 | -21979340746682042249 |
| 18 | 838330656532184312218 |
| 19 | -33803668628843391999843 |